###This error can appear when you try to install ruby gems follow this steps:
###Error: no such file to load --zlib 1. sudo apt-get install zlib1g zlib1g-dev 2. cd /usr/src/ruby-1.9.2-p180/ext/zlib/ 3. sudo ruby extconf.rb 4. sudo make 5. sudo make install
###Error: no such file to load --openssl 1. sudo apt-get install openssl libssl-dev 2. cd /usr/src/ruby-1.9.2-p180/ext/openssl/ 3. sudo ruby extconf.rb 4. sudo make 5. sudo make install
###Error: Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. 1.sudo apt-get install nodejs-dev
###An error occured while installing mysql2 1.sudo apt-get install libmysqlclient-dev 2.sudo gem install mysql2
###An error occured while installing sqlite3 1.sudo apt-get install libsqlite3-dev 2.sudo gem install sqlite3
###PhpMyAdmin sudo ln -s /etc/phpmyadmin/apache.conf /etc/apache2/conf.d/phpmyadmin.conf
then you can have resolved your problem